问题
I am using Postgres in a Rails project and I have discovered that I need to change all of my varchar datatypes to citext. Rather than do this by hand, I want to just create a migration that loops through all of the models and their attributes and converts them as necessary.
Most of these models are empty, so it's not a matter of instantiating them. I need to find out if ActiveRecord "knows" what the datatype of its corresponding database column is.
回答1:
@model.column_for_attribute('title').type
That might be what you're looking for.
来源：https://stackoverflow.com/questions/16321032/how-can-i-get-the-datatype-of-an-attribute-from-a-rails-model